A typical fluidizable bed includes a receptacle and a porous diffuser board that divides the receptacle into a plenum and a fluidizable medium container above the plenum. A fluidizable medium, such as tiny spherical particles, occupies the fluidizable medium container. A filter sheet overlies the fluidizable medium. In operation a fluidizing medium such as ambient air is pressurized and introduced into the plenum. The air flows through the diffuser board, through the fluidizable medium, and exhausts through the filter sheet. The flow of air through the fluidizable medium imparts fluid-like properties to the fluidizable medium so that the medium acts as a quasi-fluid. Fluidizable beds are used for burn victims or other patients who have skin disorders such as pressure ulcers or who are at high risk of developing skin disorders as a result of long term confinement in bed. Some fluidizable beds include a more conventional, non-fluidizable upper body or torso section corresponding approximately to the torso of a bed occupant.
Despite the advantages of fluidizable beds they do not offer certain capabilities which are not uncommon in more conventional beds. One such capability is an occupancy status detection capability which can detect the presence or absence of an occupant and changes in that status. Occupancy status capability is typically used to alert a caregive of the unauthorized departure of the bed occupant from the bed.